The present invention relates to a pneumatic sander which has an exhaust assembly with a control valve to change the passages in the assembly so as to guide the powder during grinding to desired position.
A conventional pneumatic grinding device 10 is shown in FIGS. 1 and 2, and includes an annular cover 17 which is connected to an underside of a body 11 and a motor shaft balancer (not shown) is rotatably received in the body 1. A sanding disk or sanding pad 16 is driven by the motor shaft balancer and located at an underside of the annular cover 17. A block 14 extends radially outward from the body 11 and an inlet 12 and an outlet 13 are respectively defined through the block 14 and communicate with an interior of the body 11. Pressurized air is introduced into the body 11 via the inlet 12 and flows out from the outlet 13. A tube 171 extends from the annular cover 17 and a communication tube 18 is connected between the outlet 13 and the tube 171 so that the exhaust air flow will suck the sanding powder from the communication tube 18 and being collected in a bag 181 connected to the outlet 13. FIG. 3 shows another type of sanding powder collection system and includes an auxiliary tube 19 which has a collar 190 mounted to the block 14 and a seal 191 seals the outlet 13. The auxiliary tube 19 is connected to the tube 171 and has an open end which is connected to a hose of a vacuum cleaner 192. By this way, the sanding powder is sucked by the vacuum cleaner 192 via the auxiliary tube 19. Therefore, the sanding device has three way to deal with the sanding powder, one of which is to blow the power from the outlet 13 together with the exhaust air flow, the second is to cooperate with a bag 181 as shown in FIG. 2, and the third way is to connect a vacuum cleaner 192 as shown in FIG. 3 to suck the power. The users have to choose specific items to be connected to the block 14 or the tube 171 whichever the bag 18 or the vacuum cleaner 192 are to be used. Each way of collecting the sanding powder involves a lot of parts and takes time to install or disengage from the sanding device.
The present invention intends to provide an exhaust assembly that has a control valve which is rotated to change the passages to let the exhaust air flow go through the designated passage.
In accordance with one aspect of the present invention, there is provided an exhaust assembly of a sanding device and comprising an annular cover mounted to the motor shaft balancer and a sanding pad is connected to the motor shaft balancer. An exhaust tube extends from the annular cover and holes are defined in the sanding pad and communicate with an interior of the annular cover. A casing is engaged with the annular cover and a hosing extends from the casing. An inlet and an outlet are respectively defined through the hosing and communicate with an interior of the casing. A first passage is defined in the hosing and communicates with the aid inlet and the outlet. An extension tube extends from the hosing and communicates with the first passage and the outlet. The extension tube is engaged with the annular cover. A control valve is rotatably received in the first passage and has a first section and a second section. A through hole is defined radially through the first section and a notch is defined in an outer periphery of the second section. The first section is located to block the extension tube and the second section is located to block the outlet.
The primary object of the present invention is to provide an exhaust assembly for a sanding device wherein the sanding device can be cooperated with a dust bag or a vacuum cleaner by rotating the control member.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.